After the beaches of North Holland and Friesland were littered with moss animals, there were many questions. Where did these creatures come from in such masses and, perhaps more importantly, what do we do with that blanket of creatures on our beaches? Reinier Nauta of Wageningen Marine Research, based in Den Helder, conducted research into the animals on behalf of the municipalities of Katwijk and Ameland and concludes: simply scooping and moving is the best solution for now.
It was a unique phenomenon, told Nauta earlier. Moss animals rarely wash up in such large numbers worldwide and very little is known about the organisms anyway. The aim of the research was therefore to learn more about the critters: where do they come from, what species are there and how do we get rid of them?
It is still not known exactly where the animals floated from. This requires much larger-scale research, explains Nauta.
However, the researchers have determined why the animals wash up en masse in some places. Nauta: “This is largely due to currents. In a few places, currents come together. There is a lee, and that’s where the moss animals accumulate. You see the extremes near Katwijk and Ameland. There you have a lot of tourists and many local residents, so it’s a big nuisance.”
Not harmful, but annoying
The moss animal is an exotic species in the Netherlands. Nauta: “The population grows under the radar for a number of years, and then suddenly it pops up.” That gave the blankets with moss animals on the beaches in 2021. Nauta: “After a few years it settles down. A new balance is created with the exotic in it.”
The researchers therefore expect that the nuisance caused by the moss animals will automatically decrease in the coming years. Until then it is a matter of limiting the nuisance. Nauta: “The bugs are not harmful, but they are a nuisance.”
The stench of the bugs is also not dangerous. Nauta: “Only in the most exceptional cases can hydrogen sulfide be formed due to rot, which is toxic. But that is so rare that it does not pose a risk.” To prevent odor nuisance, he therefore has clear advice for municipalities: “It is a matter of scooping it up and depositing it somewhere else: that seems to be the most efficient and simple way.”